This invention relates to the use of compounds having the general formula ##STR3## wherein R is selected from the group consisting of --H, --CH.sub.3, ##STR4## AS PLANT GROWTH REGULATORS.
In general, plant growth regulation is accomplished by either growth stimulation at one or more of the customary growth sites, by roots, buds of flowers or by causing plant deformations such as stunting, defoliation or other malformations deisgned to change the plant growth characteristics to achieve greater yield of product.
It is desirable to effect growth regulating characteristics in various plants. A wide variety of plant growth regulating properties of certain growth regulating compounds can be observed depending upon the concentration used, the formulation used, and the type of plant species treated with compounds having such growth regulating properties. For example, these compounds are capable of increasing of beneficial or desirable features of crops such as induction of sprouting underground rhizomes of monocotyledonous plants and the induction of rooting when applied to cut ends of plants. Other plant growth regulation activities which are desirable include control of apical dominance; increase in branching on a variety of plant species; increase in protein content of plants by measurable increase of the leaf area relative to the stem area; retardation of terminal growth; increased flowering and fruiting of economic crops; prevention of lodging whereby thicker stems are produced, thus resulting in firmer and stronger plants capable of resisting natural tendencies towards lodging; stimulation of seed germination; and causing hormone or epinasty effects on plants so treated.
The compounds of the present invention may be utilized on a wide variety of plant species at various concentrations of active ingredients. Amounts of as little as 0.1 lb/acre of compound may be used. Moreover, the normal range of concentrations can be from 0.1 lb./ to 16 lbs/acre. The precise amount of acetylenic 2,6-dichlorobenzoates of this invention which should be employed in order to realize the greatest effects will depend upon the particular plant species being treated. In this regard, amounts from about 0.1 lb. to as much as 25-30 lbs/acre, when applied to the plants, will result in the desired plant response, depending upon the total amount of compound used as well as the particular plant species which is being treated. It can be considered, therefore, that the preferred range within the present invention is rates of 1/2 to 4 lbs/acre in solution such that the application rate in terms of total volume varies from about 10 to 100 gallons per acre.
Although the preferred method of application of the compounds of this invention is directed to the foliage and stems of plants, it has been found that such compounds may be applied to the soil in which the plants are growing. In such cases, the compounds will be root absorbed to a sufficient extent so as to result in plant responses in accordance with the teachings of this invention. In general, the compounds of the present invention can be produced by a process as follows: